You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the "Antispam feature" entry in the Antispam and antimalware permissions topic.

You can only use PowerShell to perform this procedure. To learn how to open the Exchange Management Shell in your on-premises Exchange organization, see Open the Exchange Management Shell.

By default, antispam features aren't enabled in the Transport service on a Mailbox server. Typically, you only enable the antispam features on a Mailbox server if your Exchange organization doesn't do any prior antispam filtering before accepting incoming messages. For more information, see Enable antispam functionality on Mailbox servers.

As a best practice, you don't need to apply antispam filters to messages from trusted partners or from inside your organization. There's always a chance that the filters will detect false positives. To reduce the chance that filters will mishandle legitimate email messages, you should typically configure antispam agents to only run on messages from untrusted and unknown sources.

To enable content filtering for internal messages, run the following command:

The Delete action takes precedence over the Reject action, and the Reject action takes precedence over the Quarantine action. Therefore, the SCL threshold for the Delete action should be greater than the SCL threshold for the Reject action, which in turn should be greater than the SCL threshold for the Quarantine action. Only the Reject action is enabled by default, and it has the SCL threshold value 7.
The Quarantine action requires a spam quarantine mailbox. For more information, see Configure a spam quarantine mailbox.

This example configures the following values for the SCL thresholds:

The Delete action is enabled and the corresponding SCL threshold is set to 9.

The Reject action is enabled and the corresponding SCL threshold is set to 8.

The Quarantine action is enabled and the corresponding SCL threshold is set to 7.

Outlook Email Postmarking validation is a computational proof that Microsoft Outlook applies to outgoing messages to help messaging systems distinguish legitimate email from junk email (reduce false positives). Postmarking was first introduced in Outlook 2007, and is enabled in Outlook by default.